25 posts
React's 45KB comes from synthetic events and compatibility layers Preact drops. At 3KB, it calls native DOM directly. Here is what that trade-off means.
Three resource hints, three different jobs. Using the wrong one wastes bandwidth and slows the current page. How each one works and when to apply it.
Domain sharding, CSS sprites, and JS concatenation were correct for HTTP/1.1. HTTP/2 turned them into anti-patterns. Here is what changed and why.
Perceived and measured performance diverge more than most developers expect. LinkedIn's skeleton screen research explains why, and when skeletons hurt.
The correct image for any device depends on viewport width, pixel density, and connection speed. srcset and sizes make that computable at the HTML level.
Google's profiling found 30-50% of bandwidth goes to below-fold images. loading="lazy" defers them, but two cases where it actively hurts LCP.
All blogs in the React & JS Performance series in reading order, plus quick reference on layout thrashing, will-change, passive listeners, and INP.
How to answer practical frontend performance interviews in React: a seven-area framework—rendering, network, mobile, bundles, assets, memory, and measurement.
Your 2MB bundle isn't fate. How bundlers merge modules, why tree shaking fails silently, and how to split code so users only load what they need.
How image formats, font loading, and third-party tag managers silently destroy LCP and CLS scores, and the exact fixes for each that actually work.
How V8's generational garbage collector works, why high allocation rate causes jank, and practical strategies to reduce GC pressure in frontend code.
Budget Android devices run your JS 5-10x slower than your MacBook. Content-visibility, CSS containment, touch scroll, and real debugging on low-end hardware.
Why React SPAs refetch data you already have, and how to fix it: HTTP cache headers, stale-while-revalidate, request deduplication, and prefetch strategies.
CPU-heavy tasks block the UI — Web Workers fix that. Integrate Workers in React with Comlink, custom hooks, and Vite, with before/after profiling results.
10,000 DOM nodes is slow even if they're not visible. When to paginate, when to infinite scroll, when to virtualize — and the real cost of each approach.
How startTransition and useDeferredValue fix frozen inputs and laggy UIs by separating urgent updates from deferred ones — with real before/after examples.
Most React memoization is premature. This breaks down when memo, useMemo, and useCallback actually help and when they add memory overhead with no real gain.
Render phase vs commit phase, reconciliation and fibers, what triggers re-renders, referential equality traps, context pitfalls, and React 18 batching.
How Lottie works: JSON After Effects timelines rendered by cross-platform runtimes. Why Airbnb chose vector JSON over GIF and video for UI animations.
How Meta StyleX compiles JS-authored styles into atomic static CSS. No runtime injection, smaller bundles, and why the build-time approach matters at scale.
At 60Hz the browser has ~16.6ms per frame for JS, layout, and paint. Why load scores miss jank and what it means for trading and live data UIs.
Redux, Zustand, Jotai, and Valtio compared from the inside. Centralized, atomic, and proxy-based React state patterns and when each one wins on scale.
React error boundaries use class lifecycles, not hooks: what render errors they catch, what async and event errors they skip, and how to structure fallbacks.
Parse → DOM → CSSOM → Layout → Paint → Composite. What the main thread does each frame, what jank physically is, and how to stop causing it.
Browsers share one CSS model; Figma uses WASM and GPU shaders. Where design-to-code breaks: radius, strokes, blur, gap, and what to verify before you build.